Good advice from Ian.... also make sure that the plant is getting
appropriate lighting along with proper nutrients, possibly via a good
aquatic plant fertilizer.... Some Swords can be cultivated more
easily by growing them as marginals (half or mostly out of the water
with constant heavy moisture in the root zone) I have a red melon
sword that has been reproducing profusely for the last couple years
using this method. If you want more details on this, post again.